Improvement in marine compasses



E. s. RITCHIE.

Mari'ne Compass.

Patented July 19. 1870.

E l Alli mommy I m- WZQJ MPETERS, PHOTO LITHDGRAPHE ,setts, have made anew and useful invention having and prevent the breakage of such glassduring the ring in place upon the glass, as well as from any sub- -ringheld in place by screws. Sometimes I also placed In doing this, 1 formthe compass-bowl A with an extending entirely around the .periphery ofthe glass EDWARD s. eironlnor BROOKLINE,J'MASSAGHUSETTS.

Le tters Palent No. 105,492, dated July I9, 1870.

m IMPROVEMENT IN'MARINE compasses.

'l'he Schedule referred to in these Letters Patent and making part ofthe same.

To all persons towhom these presents may come.-

Bejt known that I, EDWARD S. Rrrcnrn, of Brook- 1 line, of the county ofNorfolk and State of Massachureference to Marine Compasses, havingtheir. bowls filled with a'liquid; and I do hereby declare the same tobefully described as follows, reference being bad to the accompanyingdrawing, of which Figure 1 is a top view, and

Figure 2, a transverse section of a compass-bowl with its glass setthereon in accordance with my invention.

The object or purpose of my improvement is to se-. curely hold the giassin place-with a water-tight joint,

act of setting down the screws for confining the capsequent change,resulting from the expansion of the glass on any of the parts about it,or otherwise.

In the common way, heretofore practiced by me, of arranging the Indiarubber packing, it has been placed in a groove disposed underneath the,glass, the latter being forced down upon the packing by a capa thinpacking over the glass and between it and/the cap-ring. v

The difliculty experienced inthis method of packing the glass plate ofthe compass-bowl was that an irregular pressure was frequently exertedon the glass by the cap 'ing, which, by subsequent changes oftemperature, or-othcr cause,- reudered the glass plate liable to beingbroken; in fact breaka, ;e of it-was so common as to cause me to devisea better or my present plan of accomplishing the enddesired.

annular rebate or socket, a, of a diameter somewhat larger than that ofthe glass plate B, viz., large enough for the socket to re'ceivethepacking O, which is a strip of vulcanized India rubber, or itsequivalent,

plate.

In order to centralize the glass plate properlythere may be an auxiliarysocket rebate or annular space, 1), leading .out of and below thepacking-socket, in manner asrepresented in fig. 2.

Next, I construct the cap-ring D with an annular lip, e, to extendaround it and from its lower surface, and torest directly upon andaround the India rubber packing.

This lip may beitriangular, or have any other proper form initstransverse section. I prefer to make it, in such sectidn, a right-angledtriangle, or thereabout.

When the cap-ring is pressed down by its series of screws, the lip willbe forced upon and into the packing, and will expand it laterally, so asto cause it to fit closely to the periphery of the glass and to theeucompassiug shoulder and bottom of the recess, whereby a water tightjoiut will be "formed between them, without danger of-breakage of theglass or any undue pressure being excited, which, from any cause as setforth, ,or otherwise, would be liable to produce injury to the glass.

I claim- In the compass-bowl as described, the cap-ring as provided withthe lip and the elastic packing, as arranged around and against theperiphery of the glass plate, and in a rebate extended around such, thewhole being as described, in order that, when the capring is screweddown, the packing-ring may be expanded by the lip, in manner and for thepurpose as set forth.

Also, the compass-bowl as made with the main and auxiliary rebatesarranged init and with the glass plate, in manner as described, and ashaving thepack- Witnesses:

- R. 'H. EDDY, J. R. SNOW.

